a. Field of the Invention
The invention relates to an elevating mechanism, and more particularly, to an elevating mechanism used in a projection apparatus.
b. Description of the Related Art
FIG. 1 shows a conventional height-adjusting device 100 for adjusting the height of a projection apparatus. As shown in FIG. 1, the height-adjusting device 100 includes a connection part 101, a leg 107, a push button 109, and a resilient member 111. The connection part 101 includes a groove 103 and a rack 105, and the push button 109 is disposed outside a housing of the projection apparatus 100 to be pushed inwardly by a user. When a user presses the push button 109, the push button 109 forces the leg 107 to slide along the groove 103, and meanwhile a protrusion part 115 of the leg 107 leans against the resilient member 111 to deform the resilient member 111 and enable the resilient member 111 to move along the rack 105. When the push button 109 is not pressed, the leg 107 is held in position through the engagement of the resilient member 111 and the rack 105. Therefore, the height of a projection apparatus is allowed to be adjusted.
Taiwan patent No. I232344 discloses an adjustable support stand for a projection apparatus, where a ratchet with multiple teeth is disposed inside a ratchet casing. When the ratchet sticks out from the ratchet casing, a pawl may engage with one corresponding tooth of the ratchet to adjust the height of the support stand. U.S. Pat. No. 5,855,278 discloses a lift device having a cylinder and a coupling cover. The cylinder has a heart-shaped guide groove, and an engagement end of the coupling cover uni-directionally slides along different sections of the heart-shaped guide groove.